Effect of indium composition ratio on solution-processed nanocrystalline InGaZnO thin film transistors

The effects of the indium content on characteristics of nanocrystalline InGaZnO (IGZO) films grown by a sol-gel method and their thin film transistors (TFTs) have been investigated. Excess indium incorporation into IGZO enhances the field effect mobilities of the TFTs due to the increase in conducting path ways and decreases the grain size and the surface roughness of the films because more InO2- ions induce cubic stacking faults with IGZO. These structural variations result in a decrease in density of interfacial trap sites at the semiconductor-gate insulator interface, leading to an improvement of the subthreshold gate swing of the TFTs.